Structural Engineering and Mechanics
Volume 17, Number 1, 2004, pages 29-50
DOI: 10.12989/sem.2004.17.1.029
Crack growth life model for fatigue susceptible structural components in aging aircraft
Karen C. Chou, Glenn C. Cox and Allison M. Lockwood
Abstract
A total life model was developed to assess the service life of aging aircraft. The primary focus of this paper is the development of crack growth life projection using the response surface method. Crack growth life projection is a necessary component of the total life model. The study showed that the number of load cycles N needed for a crack to propagate to a specified size can be linearly related to the geometric parameter, material, and stress level of the component considered when all the variables are transformed to logarithmic values. By the Central Limit theorem, the ln N was approximated by Gaussian distribution. This Gaussian model compared well with the histograms of the number of load cycles generated from simulated crack growth curves. The outcome of this study will aid engineers in designing their crack growth experiments to develop the stochastic crack growth models for service life assessments.
Key Words
crack growth; fatigue; aging aircraft; response surface method; central limit theorem; structural reliability; Gaussian distribution; statistical analysis; Kolmogorov-Smirnov test; point estimate method.
Address
Karen C. Chou<br />Department of Mechanical & Civil Engineering, 205 Trafton Science Center E., <br />Minnesota State University, Mankato, MN 56001, U.S.A. <br /><br />Glenn C. Cox<br />Lockwood Greene Engineers, Knoxville, TN, U.S.A.<br /><br />Allison M. Lockwood<br />Department of Civil & Environmental Engineering, University of Tennessee, Knoxville, U.S.A.